Lactational amenorrhea

Will breastfeeding prevent me from getting pregnant?

Breastfeeding can prevent pregnancy under certain conditions. When breastfeeding is used to prevent pregnancy, it is called the lactational amenorrheic method, or LAM. Done properly, it can protect mothers from having another child while caring for a young baby. This also helps the second child by reducing the child's chances of being born premature or small. LAM is safe, free, and generally effective; mothers who use it properly have a low chance of getting pregnant. It can be combined with barrier methods for extra protection. LAM only works during the first six months after birth and before the baby has started solids, and only if the mother breastfeeds exclusively and frequently.

A) The lactational amenorrheic method

Breastfeeding can prevent ovulation and periods. Without ovulation, mothers cannot become pregnant. Using breastfeeding to prevent pregnancy is called the lactational amenorrheic method (LAM) as amenorrheic means no periods.

Done properly, LAM protects mothers from becoming pregnant while breastfeeding and caring for a young baby. It also protects the second child, preventing it from being born too soon after a sibling. Those children who were conceived within six months of their mother delivering a first child are more likely to be born premature and small. (Conde-Agudelo 2006).

Mothers who use the LAM method properly have been reported to have a 0 to 7% chance of getting pregnant. (Van der Wijden 2015). When no contraception is used, breastfeeding mothers delay the birth of their next baby by 8 months, compared to infant formula-feeding mothers (Rosner 1990). 

LAM has many advantages, including being:

  • Safe
  • Free
  • Generally effective

It can be combined with barrier methods for extra protection.

B) Criteria for LAM

LAM only works when ALL four of the following conditions are met (Berens 2015):

  1. The baby is exclusively breastfeeding.
    1. The baby does not receive any infant formula or solid foods.
    2. The baby may receive medications and vitamin D.
    3. During periods of mother-baby separation, mothers must express for every feed that they miss and separations should be infrequent. 
  2. There must not be any long gaps between feeds.
    1. The baby must breastfeed at least seven times over 24 hours.
    2. The baby may have only one long sleep in a 24-hour period and it must last no more than five hours.
  3. The baby must be less than six months old.
  4. The mother must not have had a period. If exclusively breastfeeding, bleeding for the first 8 weeks after birth is generally not caused by period bleeding.


Berens P, Labbock M, and the Academy of Breastfeeding Medicine. ABM Clinical Protocol #13:Contraception During Breastfeeding. Breastfeeding Medicine 2015:10(1) Revised 2015
Conde-Agudelo A,  Rosas-Bermúdez A,  Kafury-Goeta AC. Birth spacing and risk of adverse perinatal outcomes: a meta-analysis. JAMA. 2006 Apr 19;295(15):1809-23

Rosner AE, Schulman SK. Birth interval among breast-feeding women not using contraceptives. Pediatrics. 1990 Nov;86(5):747-52

Van der Wijden C, Manion C. Lactational amenorrhoea method for family planning. Cochrane Database Syst Rev. 2015 Oct 12;2015(10):CD001329